I don't think anything beyond 1.0.x is available for Maemo. For instance. the latest Qt SDK 1.1 shows mobility is at 1.0.2 for Maemo here:
http://labs.qt.nokia.com/2011/05/04/...-1-1-released/.

1.0.2 wouldn't seem to have the organizer module as it does not exist in the API for that version here:
http://doc.qt.nokia.com/qtmobility-1.0/index.html.

I'm not sure if the versions in extras-dev work or not, but there are packages for Qt Mobility 1.1. For example, this package may be the organizer API you need:
libqtm-11-organizer_1.1.0-0fn~fremantle11_armel.deb, where I found here:
http://repository.maemo.org/extras-d...qt-mobility11/

You can always fall back on the calendar-backend official API.